The present invention relates to a fastening system for a garment and more particularly to an improved mechanical fastening system for a garment such as a disposable diaper, a diaper cover or incontinence pants.
As a fastening system for a garment of this type, a conventional tape or surface fastener comprises a combination of a hook panel and a loop panel respectively having a plurality of hook and loop elements (commonly known under the trade mark VELCRO TAPE or MAGIC TAPE). With this fastening system, hooks and loops of both panels extending substantially in vertical directions relative to the panels are brought into mechanical engagement as the hook panel and the loop panel contact one another.
FIGS. 5 and 6 are side view illustrations of a plurality of hook elements 17 on a hook panel 13 engaged with a plurality of loop elements 25 on a loop panel 14. Referring to FIG. 5, the hook panel 13 engages with the loop panel 14 as the hook panel is pressed on the loop panel in a direction indicated by arrow A and released therefrom as the hook panel is pulled vertically as indicated by arrow B. Referring now to FIG. 6, these two panels 13, 14 are tensioned, when they are pulled in horizontally opposite directions as indicated by arrows C, D from their mutually engaged states as illustrated by FIG. 5. FIG. 6 reveals that many of the hook elements 17 are positively brought into engagement with the corresponding loop elements 25. In the state illustrated by FIG. 5 on the other hand, the hook elements 17 are merely inserted into spaces defined among the loop elements 25 and only a few of the hook elements 17 are in engagement with the corresponding loop elements 25. As a consequence, the hook panel 13 can be easily released from the loop panel 14 as the hook panel 13 are pulled upward from the loop panel 14.
With respect to such a fastening system, Japanese Laid-Open Patent Application No. Hei4-276251 discloses that a loop panel may be intermittently bonded to a garment to facilitate many of the hook elements being caught by corresponding loop elements as a hook panel is horizontally pulled.
When a garment is placed on a wearer and fastened by engaging a hook panel with a loop panel of a fastening system, the hook panel is sometimes released from the loop panel due to a vertically oriented force carelessly exerted on the fastening system which tends to release the hook panel from the loop panel. To avoid such a situation, there is a demand for an improved fastening system such that, when a garment is placed on a wearer, a mutual engagement of these two panels cannot be easily released simply by an unintentional movement of the hook panel in the direction vertical to the loop panel but released only by positively pulling the hook panel in the vertical direction when it is desired to take off the garment from the wearer. While the previously mentioned Laid-Open Patent Application No. Hei4-276251 discloses a means ensuring that a hook panel and a loop panel be engaged with each other as the hook panel is moved in a horizontal direction relative to the loop panel, no means is disclosed by which an engagement of these two panels can be ensured as the hook panel is moved in the vertical direction relative to the loop panel.
In view of the problems as described above, it is a principal object of the invention to provide a fastening system for a garment to ensure that a hook panel is not easily released from a loop panel even if the hook panel is moved in a vertical direction away from the loop panel.
The object set forth above is achieved, according to the invention, by a fastening system attached to a waist region of a backsheet of a garment. The fastening system includes a pair of supporting tape members positioned at opposite side edges of the waist region. Each supporting tape member includes a top surface and has a first end secured to the corresponding side edge of the waist region and a second end extending outward beyond the corresponding side edge of the waist region. The fastening system further includes a pair of hook panels attached to the pair of supporting tape members, and a loop panel provided on an outer surface of the backsheet at a location appropriate for releasably engaging the pair of hook panels.
Each hook panel includes a base panel and a plurality of rows of hook elements. The base panel has a top surface and a back surface. A width of the base panel is defined by upper and lower side edges thereof in parallel with each other. The rows of hook elements extend vertically from the top surface of the base panel. The back surface of the base panel includes a secured region and a non-secured region. The secured region is secured by an adhesive agent applied over the full width thereof to the supporting tape and is outwardly adjacent to the first end of the associated supporting tape member. The non-secured region is not directly secured to the supporting tape and is outwardly adjacent the secured region and inwardly adjacent the second end of the associated supporting tape member. The hook elements are coextensive with the non-secured region wherein the number of the rows of the hook elements in the non-secured region is smaller than the number of the rows of the hook elements in the secured region.
In accordance with the present invention, each hook panel is capable of being progressively released from the loop panel by grasping the second end of the associated supporting tape member and pulling toward the first end of the associated suporting tape member. The rows of the hook elements in the non-secured region extend transversely of the direction in which the hook panel is progressively released from the loop panel. The hook elements which are coextensive with the non-secured region include from 2 to 20 rows of hook elements. A length of the non-secured region, as measured in the direction in which the hook panel is progressively released from the loop panel, is smaller than that of the secured region.
In accordance with a preferred aspect the present invention, the base panel has a bending resistance less than 0.1 g as measured by a stiffness tester available under the trademark GURLEY. Such a device is used in determination of all bending resistances disclosed in this application.